Question: Umaima is 3 times as old as Vanessa and is also 18 years older than Vanessa. How old is Vanessa?
We can use the given information to write down two equations that describe the ages of Umaima and Vanessa. Let Umaima's current age be $u$ and Vanessa's current age be $v$ $u = 3v$ $u = v + 18$ Now we have two independent equations, and we can solve for our two unknowns. Since we are looking for $v$ , and both of our equations have $u$ alone on one side, this is a convenient time to use elimination. Subtracting the second equation from the first equation, we get: $0 =$ $3v$ $-$ $ (v + 18)$ which combines the information about $v$ from both of our original equations. Solving for $v$ , we get: $2 v = 18$ $v = 9$.